Device for withdrawing castings from mould of continuous metal casting machine

ABSTRACT

A device for withdrawing a casting from a mold in a continuous metal casting machine comprising an appliance which represents arms adapted to grip the casting. The arms are articulated on carriages and are disposed at an acute angle to the longitudinal axis of the casting in the direction of its withdrawal. The carriages are aligned axially with one another and with the longitudinal axis of the casting. They traverse in opposite, relative to each other, directions along the screws having a thread directed in opposite sides along the screw length and provided with a reversing drive.

United States Patent 1 Milyaev et a1.

1 1 DEVICE FOR WITHDRAWING CASTINGS FROM MOULD OF CONTINUOUS METAL CASTING MACHINE [76] Inventors: Boris Fedorovich Milyaev, 9 ulitsa Sokolinol gory, 3, kv. 37; Zakhar Alexeevich Ozeshnikov, Otkrvtoe Shosse, 29, korpus 5, kv. 28; Nikolai Maximovich Tuchkevich, lzmailovskoe shosse, 1 l3. kv. 43, all of Moscow, U.S.S.R.

[22] Filed: May 7, 1974 [211 Appl. No.: 467,843

Related US. Application Data [63] Continuation of Ser. No. 340,746, March 13, 1973.

abandoned.

[52] US. Cl. 164/282; 164/82 [51] Int. Cl 322d 11/12 [58] Field of Search 164/82, 84, 282

[56] References Cited UNITED STATES PATENTS 1,088,171 2/1914 Pehrson 164/282 X [451 July 15, 1975 1,444,953 2/1923 Crane 164/84 FOREIGN PATENTS OR APPLICATIONS 569.367 ll/l957 Italy 164/282 Primary Examiner-R. Spencer Annear Attorney, Agent, or FirmHolman & Stern [57] ABSTRACT 3 Claims, 4 Drawing Figures DEVICE FOR WITHDRAWING CASTINGS FROM MOULD OF CONTINUOUS METAL CASTING MACHINE This is a continuation, of application Ser. No. 340,746, filed Mar. 13, 1973, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to devices for withdrawing castings from a mold of a continuous metal casting machine in the open air, in a protective atmo sphere and/or under vacuum. The castings obtainable with the help of the above device are preferably consumable electrodes intended for secondary remelting in electroslag, vacuum-arc and induction furnaces.

PRIOR ART A device is known in the art for withdrawing a casting from the mold of a continuous metal casting machine comprising a screw reversing drive installed on a frame, with each of the screws mounting a carriage with an appliance interacting at first with a dummy bar at the beginning of the process and then with the casting being withdrawn (extracted) from the mold of the casting machine.

However, in this device, the driving screws feature insufficient length which results in producing castings having small lengths, with this in turn being a limiting factor restricting the capacity of the melting furnace.

Due to the technological conditions available and the possibilities of machine tools, the fabrication of the longer driving screws is not feasible.

As to the semi-continuous metal casting machines equipped with the known casting-withdrawal devices, they feature low production rates. This can be attributed to the fact that after each heat has been poured, it is necessary to stop the device, withdraw the casting, strip the pouring fixture and then again prepare the mold, dummy bar and metal reservoir for pouring the subsequent heat. In this case too much time is consumed on the preparatory jobs and heavy losses of metal up to are encountered after trimming the end faces well as the bottoms in the metal reservoirs.

1n the semi-continuous casting of metals, the production of longer castings requires longer castingwithdrawal devices and this results in a higher cost of the casting machine and is associated with various problems of both constructional and technological natures.

The devices for withdrawing castings employed in the continuous metal casting machines comprise friction rollers which are liable to slip when the casting hangs up in the mold whereupon the casting process is discontinued.

In this connection, the devices incorporating the rollers are less reliable in service than those with screw pairs. Moreover, friction devices are unsuitable for operation with programmed withdrawal of the casting from the machine mold when the machine is to be stopped for a short time to meet crystallization conditions.

OBJECTS AND SUMMARY OF THE INVENTION The main object of the present invention is to provide a device for withdrawing (extracting) a casting from a mold in a continuous metal casting machine with such an appliance for gripping the casting which excludes the slippage of the grip along the casting, ensures programed traverse of the casting and stabilizes the casting process.

Another but no less important object of the invention is to provide a continuous (uninterrupted) withdrawal of the casting ensuing from gripping it alternately by the arms of reciprocating carriages.

Still another object of the invention is to diminish the length of the device and to provide a possibility of fitting it with a cutting means to obtain blanks of a specified length.

These and other objects are accomplished by the provision of a device for withdrawing a casting from a mold in a continuous metal casting machine comprising screws mounted on a frame and linked mechanically with a reversing drive and carriages reciprocating along the screws togehter with an appliance interacting with the casting being withdrawn, wherein, according to the invention, the appliance represents arms gripping the casting arranged at an acute angle to the longitudinal axis of the casting in the direction of its withdrawal and articulated on the carriages aligned axially with one another and with the longitudinal axis of the casting, with each of the screws having a thread directed in opposite directions and ensuring the longitudinal transfer of the carriages in mutually opposite directions.

The above-described device excludes the slipping of the grip along the casting. It operates as a continuous device, ensuring the production of the castings featuring considerable length due to the casting being alternately gripped by the arms of one carriage and then by another carriage.

The device is compact and may be furnished with means for cutting the casting to specified-length blanks. It is universal and is suitable for the withdrawal from the mold of the castings emerging vertically, horizontally or obliquely. Due to an improved design of the gripping appliance the length of the device is decreased by onehalf, with its cost being thereby also reduced.

It is advisable that each arm be made with a loose end, with the device being equipped with elastic members connecting the loose ends of the arms to the carriages. This will provide for a more efficient intrusion of the arms into the casting.

It is desirable that the device be furnished with a pipe having longitudinal through slots overlapped by the fastened thereto, carriages with the arms entering the above slots and interacting at first with a dummy bar and then the casting, with the pipe being coupled with one end to the mold, while its other end mounts an attached cover with a hole for the passage of the dummy bar and with packings adapted to hermetically seal the pipe interior and arranged in the joints between the pipe and the mold, carriages, cover and the rods of the elastic members.

With the above arrangement, the pipe allows protecting the exterior of the casting, e.g. produced from hightemperature steel, from oxidation. ln some castings subject to abrupt cooling in the air, cracks may arise. Hence, the castings in such alloys may be produced either under vacuum or in a neutral gaseous atmosphere. The vacuum casting (pouring) of metal allows enhancing the quality of castings. In this case, the external surface of the casting intended for secondary remelting as an electrode does not require machining.

BRIEF DESCRIPTION OF THE DRAWINGS,

The present invention will be better understood from a consideration of a detailed description of an exemplary embodiment thereof, when lead in conjunction with the accompanying drawings, wherein:

FIG. 1 is a longitudinal fragmentary partly in section and partly in elevation view present device,

FIG. 2 is a fragmentary longitudinal enlarged view partly in section and partly in elevation of the carriages with arms having loose ends which are coupled with the elastic members;

FIG. 3 is a sectional view taken along the line llllll of FIG. 2; and

FIG. 4 is a sectional view taken along the line lVlV of FIG. 1.

DETAILED DESCRlPTlON OF THE PREFERRED EMBODIMENTS A device for withdrawing a casting from a mold in a continuous metal casting machine comprises a frame 1 (FIG. [)to which are fastened screws 2 which receive a reversing motion from a drive 3 mounted on the frame 1.

Each of the screws 2 is provided with a thread running in opposite directions along its length, and along which thread, a nut 4 traverses transmitting the longitudinal motion to a carriage S. The latter is a pipe section placed on a pipe 6 which is capable of reciprocating therealong on being set in motion by the drive 3 through a pair of worm gears 7 and 8 (FIG. 4) and the nut 4.

An appliance interacting with a casting 9 (at first with a dummy bar not shown in the drawing) represents arms 10 (FIGS. 1, 2 and 3) adapted to grip the casting 9, with the arms being arranged at an acute angle a to the longitudinal axis of the casting 9 in the direction of its withdrawal (indicated by arrow A) and articulated to the carriage via a hinge or pivot 11. Each arm may be provided with a loose end to which is connected a rod 13 hermetically sealed by a packing 14 and an elastic member 12 is articulated at one end to the rod 13 (FIG. 2) while the other end of the elastic member 12 is connected to the carriage 5. The pipe 6 is fastened to the frame 1 and is provided with ducts 15 (FIGS. 3 and 4) for a cooling agent. One end of the pipe 6 (FIG. 1) is fixed on the body of a mold l6 and its other end is closed with a cover 17 provided with a hole for the passage of the dummy bar.

In another exemplary embodiment of the device, use may be made of a solid cover without the hole if the pipe 6 accommodates knives 18 for cutting the casting 9. The pipe 6 is fitted with a peephole 19 for visual observation of the metal casting process, with a fusible diaphragm 20 melting out in case a hard skin of the casting 9 breaks down and with longitudinal through slots 21 into which the arms 10 are introduced. The mold 16 is coupled with a metal reservoir 22 located in a vacuum chamber 23.

The device operates in the following manner:

The dummy bar is introduced into the mold 16 with the carriage arms 10 being moved aside and the carriages 5 positioned in their extreme positions. The diaphragm 20 is set up and sealed as well as all the hatches, covers and gate valves. Thereafter, the interior of the pipe 6 of the device is evacuated whereupon the mold l6 and the interior of the pipe 6 are filled with a neutral gas, if required, the other spaces and ducts provided in such places where cooling is needed being charged with the cooling agent. As soon as all the preparatory jobs are completed and a requisite vacuum is created in the device interior or it is filled with a protective medium, molten metal is supplied from a melting chamber (not shown in the drawing) to the metal reservoir 22 arranged in the vacuum chamber 23. After a period of time necessary for the formation of a hard skin on the casting 9 has elapsed, the reversing drive 3 is activated and sets in rotation the screws 2 thereby transmitting motion to the carriages 5 via the nuts 4. The carriage 5 shown in FIG. 2 on the right-hand side traverses from the right to the left-hand side, performing its working stroke. Meanwhile, several pairs of its arms 10 intrude and grip at first the dummy bar and then the casting 9 from two opposite sides. The elastic members (springs) 12 contribute to a better cohesion between the arms and casting 9 until the right-hand carriage 5 completes its stroke along arrow A, with the stroke being equal to the length of a threaded in one direction portion of the pulling or driving screws 2. At the same time, the left-hand carriage 5 performs its idle stroke traversing in the opposite direction. lts arrnsll) are shown slightly above to illustrate that they are not associated in a power aspect with casting 9. Actually, they slip along the external surface of the casting under the action of the springs 12. After the right-hand carriage 5 has completed its working stroke and the lefthand carriage 5 its idle run, the direction of rotation of the screws 2 is reversed, whereupon the left-hand carriage 5 will perform its working stroke and the righthand carriage 5 its idle run, providing thereby a forward movement of the casting 9 along arrow A. This alternation and interchange of the drawing functions of the left and right-hand carriages 5 may last as long as is required for the operation of the machine. Actually, the alternate withdrawal of the casting by the carriages may be effected continuously. The arms 10 will intrude automatically, depending on the direction of motion, and grip the casting 9 during the working stroke and release it also automatically during the idle run.

What we claim is:

l. A device for withdrawing a casting from a mold of a continuous metal casting machine comprising: a frame; screws mounted on said frame on opposite sides of the path of said casting, each of said screws having oppositely threaded portions running along its length to provide opposed reciprocating motion of carriages mounted thereon; said carriages being aligned axially with one another and with the longitudinal axis of the casting; an arm mounted on each carriage for gripping the casting, said arm being disposed at an acute angle relative to the longitudinal axis of the casting in the direction of its withdrawal and articulated on said can riages; and a reversing drive system linked mechanically with said screws.

2. A device as claimed in claim 1, wherein each said arm is made with a loose end and provision is made for elastic members, each of them serving for connecting the loose end of the arm to said carriage.

3. A device as claimed in claim 2 further comprising a pipe having longitudinal through slots, one end of said pipe being connected to said mold and the other end mounting a cover provided with a hole for the passage of a dummy bar fastened thereto; said carriages being attached to said pipe and overlapping its slots into which enter said arms fastened to said carriages and interacting at first with the dummy bar and then with the casting; and packing adapted to seal said pipe interior and located in joints between said pipe and said mold,

carriage, cover and rods of the elastic members.

i l i i 

1. A device for withdrawing a casting from a mold of a continuous metal casting machine comprising: a frame; screws mounted on said frame on opposite sides of the path of said casting, eaah of said screws having oppositely threaded portions running along its length to provide opposed reciprocating motion of carriages mounted thereon; said carriages being aligned axially with one another and with the longitudinal axis of the casting; an arm mounted on each carriage for gripping the casting, said arm being disposed at an acute angle relative to the longitudinal axis of the casting in the direction of its withdrawal and articulated on said carriages; and a reversing drive system linked mechanically with said screws.
 2. A device as claimed in claim 1, wherein each said arm is made with a loose end and provision is made for elastic members, each of them serving for connecting the loose end of the arm to said carriage.
 3. A device as claimed in claim 2 further comprising a pipe having longitudinal through slots, one end of said pipe being connected to said mold and the other end mounting a cover provided with a hole for the passage of a dummy bar fastened thereto; said carriages being attached to said pipe and overlapping its slots into which enter said arms fastened to said carriages and interacting at first with the dummy bar and then with the casting; and packing adapted to seal said pipe interior and located in joints between said pipe and said mold, carriage, cover and rods of the elastic members. 